auth failure with user=<> on server

[gene-git]

Describe the bug
2.9.3 works fine.
Problem with both 2.94 and 2.9.5 - client web shows popup saying STARTLS not supported.

On dovecot mail server i see :
Disconnected: Connection closed (no auth attempts in 1 secs): user=<>,

Has been working perfectly prior. Not sure what I did to break it

short_login is (and always was) set to on in case that's relevant - startls is on:
imap_secure = "TLS"

Log shows:
[...] INFO[ERROR]: MailSo\Net\Exceptions\SocketUnsuppoterdSecureConnectionException: STARTTLS is not supported in /usr/share/webapps/snappymail/snappymail/v/2.9.5/app/libraries/MailSo/Imap/ImapClient.php:112
Stack trace:
#0 /usr/share/webapps/snappymail/snappymail/v/2.9.5/app/libraries/RainLoop/Model/Account.php(241): MailSo\Imap\ImapClient->Connect()
...

This has been working fine up to version 2.9.3 - then something broke - snappymail config has not changed.
Other clients (iphone, android, thunderbird on desktop continue to work fine as does 2.9.3).

Get same error when try to login as admin - which was a bit of a surprise as I would think admin login does not attempt to connect to imap.

Any advice on where I can look to fix this?

Software:
arch linux
php 8.0.13
php-fpm 8.0.13
snappymail 2.9.5 (tho I tried git master with same result)
nginx-mainline 1.21.4
dovecot 2.3.17
postfix 3.6.3

Thanks as always

[gene-git]

Fix confirmed - thank you!